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Dagne Wegary Gissa

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Dagne Wegary Gissa
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Dagne Wegary Gissa

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Now showing 1 - 8 of 8
  • Stage-gate advancement process in maize breeding
    (CIMMYT, 2021) Dagne Wegary Gissa; Tadesse, B.
    Publication
  • Molecular diversity and selective sweeps in maize inbred lines adapted to African highlands
    (Nature Publishing Group, 2019) Dagne Wegary Gissa; Chere, A.T.; Prasanna, B.M.; Tadesse, B.; Alachiotis, N.; Negera, D.; Awas, G.; Abakemal, D.; Ogugo, V.; Gowda, M.; Semagn, K.
    Little is known on maize germplasm adapted to the African highland agro-ecologies. In this study, we analyzed high-density genotyping by sequencing (GBS) data of 298 African highland adapted maize inbred lines to (i) assess the extent of genetic purity, genetic relatedness, and population structure, and (ii) identify genomic regions that have undergone selection (selective sweeps) in response to adaptation to highland environments. Nearly 91% of the pairs of inbred lines differed by 30–36% of the scored alleles, but only 32% of the pairs of the inbred lines had relative kinship coefficient <0.050, which suggests the presence of substantial redundancy in allelic composition that may be due to repeated use of fewer genetic backgrounds (source germplasm) during line development. Results from different genetic relatedness and population structure analyses revealed three different groups, which generally agrees with pedigree information and breeding history, but less so by heterotic groups and endosperm modification. We identified 944 single nucleotide polymorphic (SNP) markers that fell within 22 selective sweeps that harbored 265 protein-coding candidate genes of which some of the candidate genes had known functions. Details of the candidate genes with known functions and differences in nucleotide diversity among groups predicted based on multivariate methods have been discussed.
    Publication
  • Chapter 7. Fast-tracking the development and dissemination of a drought-tolerant maize variety in Ethiopia in response to the risks of climate change
    (The Climate-Smart Agriculture Papers, 2019) Tadesse, B.; Azmach, G.; Keno, T.; Chibsa, T.; Beyene, A.D.; Demissie, G.; Dagne Wegary Gissa; Wolde, L.; Chere, A.T.; Regasa, M.W.
    Climate change projections suggest increased frequency of drought in many parts of sub-Saharan Africa (SSA). The replacement of old varieties of maize with new drought-tolerant (DT) varieties will be crucial to respond to the future risk of drought, as it already is today. The first group of locally developed maize hybrids in Ethiopia—BH140, BH660 and BH540—were commercialised between 1988 and 1995, but were not selected for drought tolerance. Among these, BH660 remained the most popular and widely grown maize variety in the Ethiopian maize belt between 2000 and 2010, accounting for nearly 50% of maize area under improved seed. A new DT hybrid, BH661, with better agronomic performances under optimum and random drought than BH660, was identified and released in 2011. In 2016, 9000 tonnes of certified seed—enough to plant 360,000 ha—was produced and marketed. The concerted effort of breeders and seed producers as well as governmental and non-governmental extension workers drove the development, release and rapid adoption of BH661 contributing to food and income security of more than 300,000 households by mitigating the effects of climate change in Ethiopia. The success of BH661 is a valuable and timely case study for breeders, seed companies, extension agents, regulatory bodies and policy-makers striving to develop and disseminate new DT varieties in sub-Saharan Africa.
    Publication
  • Major biotic maize production stresses in Ethiopia and their management through host resistance
    (Academic Journals, 2018) Keno, T.; Azmach, G.; Dagne Wegary Gissa; Regasa, M.W.; Tadesse, B.; Wolde, L.; Deressa, T.; Abebe, B.; Chibsa, T.; Suresh, L.M.
    Biotic stresses are recently evolving very rapidly and posing significant yield losses of maize production in Ethiopia. A number of high yielding maize hybrids, initially developed as tolerant/resistant, have been taken out of production due to their susceptibility to major maize diseases. Furthermore, recent disease and insect pest epidemics have clearly shown the importance of breeding maize for biotic stresses and study the genetics of resistance to the major maize disease pathogens, insect pests and parasitic weeds. This paper gives the general perspective of the major biotic maize production stresses in Ethiopia and the interventions made locally and globally to control these stresses using host resistance. More emphasis was given to grey leaf spot (GLS), turcicum leaf blight (TLB), common leaf rust (CLR), maize streak disease (MSD), maize lethal necrosis (MLN), maize weevil, stalk borers, fall armyworm and Striga. Approaches to conducting genetic analysis and achieving durable host resistance to these stresses, where applicable, are discussed. This information will be used for breeders, private and public maize seed and grain growers who are targeting to operate in Ethiopia and Eastern Africa.
    Publication
  • Genetic variation and population structure of maize inbred lines adapted to the mid-altitude sub-humid maize agro-ecology of Ethiopia using single nucleotide polymorphic (SNP) markers
    (BioMed Central, 2017) Tadesse, B.; Semagn, K.; Das, B.; Olsen, M.; Labuschagne, M.; Regasa, M.W.; Dagne Wegary Gissa; Azmach, G.; Ogugo, V.; Keno, T.; Abebe, B.; Chibsa, T.; Menkir, A.
    Molecular characterization is important for efficient utilization of germplasm and development of improved varieties. In the present study, we investigated the genetic purity, relatedness and population structure of 265 maize inbred lines from the Ethiopian Institute of Agricultural Research (EIAR), the International Maize and Wheat Improvement Centre (CIMMYT) and the International Institute of Tropical Agriculture (IITA) using 220,878 single nucleotide polymorphic (SNP) markers obtained using genotyping by sequencing (GBS). Only 22% of the inbred lines were considered pure with <5% heterogeneity, while the remaining 78% of the inbred lines had a heterogeneity ranging from 5.1 to 31.5%. Pairwise genetic distances among the 265 inbred lines varied from 0.011 to 0.345, with 89% of the pairs falling between 0.301 and 0.345. Only <1% of the pairs had a genetic distance lower than 0.200, which included 14 pairs of sister lines that were nearly identical. Relative kinship analysis showed that the kinship coefficients for 59% of the pairs of lines was close to zero, which agrees with the genetic distance estimates. Principal coordinate analysis, discriminant analysis of principal components (DAPC) and the model-based population structure analysis consistently suggested the presence of three groups, which generally agreed with pedigree information (genetic background). Although not distinct enough, the SNP markers showed some level of separation between the two CIMMYT heterotic groups A and B established based on pedigree and combining ability information. The high level of heterogeneity detected in most of the inbred lines suggested the requirement for purification or further inbreeding except those deliberately maintained at early inbreeding level. The genetic distance and relative kinship analysis clearly indicated the uniqueness of most of the inbred lines in the maize germplasm available for breeders in the mid-altitude maize breeding program of Ethiopia. Results from the present study facilitate the maize breeding work in Ethiopia and germplasm exchange among breeding programs in Africa. We suggest the incorporation of high density molecular marker information in future heterotic group assignments.
    Publication
  • Quality Protein Maize (QPM): a guide to the technology and its promotion in Ethiopia
    (CIMMYT, 2015) Chere, A.T.; Dagne Wegary Gissa; Tadesse, A.; Tadesse, B.; Bantte, K.; Friesen, D.; Prasanna, B.M.
    This guide book introduces the nutritional benefits of QPM over conventional maize varieties and presents a brief overview of its historical development. It also provides information on QPM varieties available for commercial production in different agro-ecologies of Ethiopia and the agronomic management practices required for seed and grain production. It further presents a general guide on how to establish field demonstration plots and conduct field days on QPM varieties. It is meant to serve as a reference for extension experts, farmers and other stakeholders who are involved in the production, demonstration, and extension of QPM in Ethiopia. To some extent, it would be a useful source of information to health professionals who are involved in health extension, and to students and teachers in agricultural training centers such as Agricultural, Technical and Vocational Educational Training (ATVET) colleges.
    Publication
  • Factors that transformed maize productivity in Ethiopia
    (Springer Verlag, 2015) Abate, T.; Shiferaw, B.; Menkir, A.; Dagne Wegary Gissa; Kebede, Y.; Tesfaye, K.; Kassie, M.; Bogale, G.; Tadesse, B.; Keno, T.
    Maize became increasingly important in the food security of Ethiopia following the major drought and famine that occurred in 1984. More than 9 million smallholder households, more than for any other crop in the country, grow maize in Ethiopia at present. Ethiopia has doubled its maize productivity and production in less than two decades. The yield, currently estimated at >3 metric tons/ha, is the second highest in Sub-Saharan Africa, after South Africa; yield gains for Ethiopia grew at an annual rate of 68 kg/ha between 1990 and 2013, only second to South Africa and greater than Mexico, China, or India. The maize area covered by improved varieties in Ethiopia grew from 14%in 2004 to 40%in 2013, and the application rate of mineral fertilizers from 16 to 34 kg/ha during the same period. Ethiopia’s extension worker to farmer ratio is 1:476, compared to 1:1000 for Kenya, 1:1603 for Malawi and 1:2500 for Tanzania. Increased use of improved maize varieties and mineral fertilizers, coupled with increased extension services and the absence of devastating droughts are the key factors promoting the accelerated growth in maize productivity in Ethiopia. Ethiopia took a homegrown solutions approach to the research and development of its maize and other commodities. The lesson from Ethiopia’s experience with maize is that sustained investment in agricultural research and development and policy support by the national government are crucial for continued growth of agriculture.
    Publication
  • Meeting the challenges of global climate change and food security through innovative maize research
    (CIMMYT, 2012) Regasa, M.W.; Twumasi Afriyie, S.; Wolde, L.; Tadesse, B.; Demissie, G.; Bogale, G.; Dagne Wegary Gissa; Prasanna, B.M.
    The National Maize Research Project of Ethiopia has a well-established tradition of conducting decadal workshops on maize research, development and utilization. The first and second workshops were held in 1992 and 2001, respectively. The articles publishe
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